Complex regional pain syndrome-up-to-date

Complex Regional Pain Syndrome: a cross-sectional study of physical symptoms, disability, and psychological health in long term

Introduction

Knowledge about long-time residual symptoms, disabilities, and psychological health in complex regional pain syndrome (CRPS) is limited.

Objectives

The aim was to evaluate outcome, focusing on physical symptoms, disability, and psychological health, in individuals with CRPS through a cross-sectional survey study.

Methods

Individuals with a confirmed diagnosis of CRPS were identified through medical charts and sent validated survey forms (Disabilities of the Arm, Shoulder and Hand-Quick version, Specific Hand Surgery Questionnaire-8 questions, EuroQol 5 Dimensions 3 levels, Life Satisfaction Questionnaire-11, Hospital Anxiety and Depression Scale, Pain Catastrophizing Scale, and Sense of Coherence-29) and complementary questions.

Results

Responders (response rate: 99/238, 42%; CRPS type 1: 72%; CRPS type 2: 28%; time since diagnosis median: 59 [34-94] months) reported remaining symptoms and disability (Disabilities of the Arm, Shoulder and Hand-Quick version score: 45 [20-70]) and more improvement in type 1 than in type 2. Only 9% of individuals with CRPS reported no residual pain or discomfort. Approximately 60% had problems in daily activities, 49% had sleeping problems, and 90% experienced moderate-extreme pain with 23% still on sick leave. The Hospital Anxiety and Depression Scale survey revealed significantly higher scores than a Swedish reference population. Individuals with a low Sense of Coherence and high pain catastrophizing had worse disability and were less satisfied with their lives and physical and psychological health. A lower level of education and more anxiety were associated with worsened disability over time.

Conclusion

Individuals with CRPS suffer in the long term from pain, sleeping problems, and limitations in daily activities with occurrence of anxiety and depression, resulting in dissatisfaction with many aspects of their lives. A low Sense of Coherence and high pain catastrophizing are associated with a worse outcome. Biopsychosocial aspects should be addressed in clinical practice.

[Prospective, multicenter study of the outcome of complex regional pain syndrome after 12 months]

BACKGROUND AND OBJECTIVES

Complex regional pain syndrome (CRPS) can lead to severe pain and limited functionality in the long term. Guidelines should help to optimize treatment procedures. It should be investigated which outcome is achieved after 1 year with guideline-based therapy.

MATERIALS AND METHODS

In a prospective multicenter study, 40 patients with newly diagnosed CRPS were examined to determine how their pain and functional limitations changed within 1 year. In addition, it was investigated whether the time of diagnosis and invasive measures influence these outcome parameters.

RESULTS

All patients received physiotherapy and/or ergotherapy, treatment with glucocorticoids and/or bisphosphonates 29 (72.5%); various invasive measures were carried out in 13 (32.5%). After 1 year, both pain and functionality were significantly improved; two-thirds reported a tolerable average pain intensity. Severe functional impairment according to von Korff disability points was found after 1 year in 9 (22.5%), and a moderate or severe impairment according to medical evaluation in 6 (15%) and 3 (7.5%) patients, respectively. Earlier diagnosis and corresponding earlier start of treatment correlated with better outcome in terms of pain and functionality according to von Korff, but not according to medical evaluation. The influence of invasive procedures on the outcome parameters tended to be low.

CONCLUSION

Guideline-based treatment led to a good outcome in terms of pain and functionality in the majority of patients. Early diagnosis correlated with better outcome, so suspected cases should be referred quickly to a medical facility with appropriate expertise.

9. Chronic knee pain

INTRODUCTION

Chronic knee pain is defined as pain that persists or recurs over 3 months. The most common is degenerative osteoarthritis (OA). This review represents a comprehensive description of the pathology, diagnosis, and treatment of OA of the knee.

METHODS

The literature on the diagnosis and treatment of chronic knee pain was retrieved and summarized. A modified Delphi approach was used to formulate recommendations on interventional treatments.

RESULTS

Patients with knee OA commonly present with insidious, chronic knee pain that gradually worsens. Pain caused by knee OA is predominantly nociceptive pain, with occasional nociplastic and infrequent neuropathic characteristics occurring in a diseased knee. A standard musculoskeletal and neurological examination is required for the diagnosis of knee OA. Although typical clinical OA findings are sufficient for diagnosis, medical imaging may be performed to improve specificity. The differential diagnosis should exclude other causes of knee pain including bone and joint disorders such as rheumatoid arthritis, spondylo- and other arthropathies, and infections. When conservative treatment fails, intra-articular injections of corticosteroids and radiofrequency (conventional and cooled) of the genicular nerves have been shown to be effective. Hyaluronic acid infiltrations are conditionally recommended. Platelet-rich plasma infiltrations, chemical ablation of genicular nerves, and neurostimulation have, at the moment, not enough evidence and can be considered in a study setting. The decision to perform joint-preserving and joint-replacement options should be made multidisciplinary.

CONCLUSIONS

When conservative measures fail to provide satisfactory pain relief, a multidisciplinary approach is recommended including psychological therapy, integrative treatments, and procedural options such as intra-articular injections, radiofrequency ablation, and surgery.

Monitoring Everyday Upper Extremity Function in Patients with Complex Regional Pain Syndrome: A Secondary, Retrospective Analysis from ncRNAPain

Objective

Complex regional pain syndrome (CRPS) represents a rare complication following injury to a limb. The DASH questionnaire (disability of arm, shoulder, and hand) evaluates everyday arm function. We assessed the DASH and its subitems in comparison to patients with brachial plexus lesions or fracture controls, analysed it over time, and in relation to active range of motion (ROM), to determine patients' impairment and trajectory.

Methods

The dataset included 193 patients with upper extremity CRPS from the noncoding RNA (ncRNA) Pain cohort, 36 fracture controls, and 12 patients with traumatic brachial plexus lesions. For the clinical and psychological characterisation, questionnaires and a goniometer for the measurement of ROM were utilized. Thirty-three patients were followed up after approximately 2.5 years of guideline treatment.

Results

CRPS patients had a similar mean DASH of 54.7 (standard deviation (S.D.) ±21) as brachial plexus lesion patients (M = 51.4, S.D. ± 16.1) but different significantly from fracture controls (M = 21.2, S.D. ± 21.1). Pain and older age were predictors of the DASH. Activities requiring force or impact on the arm, shoulder, or hand were mostly affected in patients with CRPS. After 2.5 years of standard treatment, the mean DASH score fell to 41.3 (S.D. ± 25.2), weakness in leisure activities was recuperated, pain feelings were lessened, and ROM, e.g., wrist flexion, recovered by 36°. Two-thirds of patients improved in both the DASH and the ROM.

Conclusions

CRPS is as disabling as a complete loss of arm function in brachial plexus lesions and exhibits only partial recovery. Developing QuickDASH versions for CRPS patients could reduce the load of questions in clinical studies. It would be prudent to consider the unexpected age dependency of the DASH in future studies. This trial is registered with DRKS00008964.

The role of fatigue in patients with complex regional pain syndrome

BACKGROUND AND PURPOSE

Fatigue affects patients across a variety of neurological diseases, including chronic pain syndromes such as complex regional pain syndrome (CRPS). In CRPS, fatigue is often underestimated, as the focus lies in the assessment and managing of pain and sensorimotor deficits. This study aimed to investigate the prevalence, characteristics, and influence of fatigue on CRPS severity and quality of life in these patients. Such insights could enhance the clinical management of this challenging condition.

METHODS

In this prospective study, 181 CRPS patients and 141 age and gender-matched individuals with injury but without chronic pain were interviewed using the Fatigue Scale for Motor and Cognitive Function to assess fatigue. Depressive symptoms and quality of life (QoL) were also evaluated as additional outcome measures. Statistical analysis was performed to examine differences in fatigue prevalence between the groups, as well as associations with CRPS severity, pain levels, and clinical phenotype. In addition, best subsets regression was used to identify the primary factors influencing QoL. Fatigue was tested in a mediation analysis as a mediator between pain and depression.

RESULTS

CRPS patients showed significantly higher fatigue levels compared to controls (CRPS: 75 [IQR: 57-85] vs. controls: 39 [IQR: 25-57]). Based on the FSMC, 44.2% in the control group experienced fatigue, while 85% of patients with CRPS experienced fatigue (p < 0.001), of which 6% were mild, 15% moderate, and 67% severe. In CRPS severe fatigue was associated with higher pain intensities compared to no fatigue (pain at rest: p = 0.003; pain during movement: p = 0.007) or moderate fatigue (pain during movement: p = 0.03). QoL in our cohort was mainly influenced by pain (pain during movement: adj.R2 = 0.38; p < 0.001, pain at rest: Δadj.R2 = 0.02, p = 0.007) and depressive symptoms (Δadj.R2 = 0.12, p < 0.001). Subsequent analyses indicated that pain and depressive symptoms primarily impact QoL in CPRS whereas fatigue may exert an indirect influence by mediating the connection between pain and depression (p < 0.001).

CONCLUSIONS

This pioneering study investigates the prevalence of fatigue in CRPS patients and its relation to disease characteristics. Our results indicate a high prevalence of severe fatigue, strongly correlated with pain intensity, and its importance in the interaction between pain and depression in CRPS. These findings underscore the significant role of fatigue as a disease factor in CRPS. Therefore, the evaluation of CRPS-related disability should include a standardized assessment of fatigue for comprehensive clinical management.

Exploring strategies to improve clinical decision making in a chiropractic office: a case series

Background

Clinicians make clinical decisions using the dual process theory. The dual process theory comprises two approaches, System 1, based on heuristics, and System 2, involving an analytical and effortful thought process. However, there are inherent limitations to the dual process theory, such as relying on inaccurate memory or misinterpreting cues leading to inappropriate clinical management. As a result, clinicians may utilize mental shortcuts, termed heuristics, and be susceptible to clinical errors and biases that may lead to flawed decision making and diagnosis.

Methods

This case series describes four clinical cases whereby the clinicians use distinct strategies to assess and manage complex clinical presentations.

Discussion

Through the use of self-reflection and acknowledging diagnostic uncertainty, the clinicians were able to reduce common cognitive biases and provide effective and timely patient care. We discuss strategies that clinicians can implement in their daily practice to improve clinical decision-making processes and deliver quality care.

Does Platelet-Rich Plasma Deserve a Role in Accelerating the Recovery of Reflex Sympathetic Dystrophy Following Distal Radius Fracture?

Introduction

This study was to evaluate the efficacy of multiple platelet-rich plasma injections in reflex sympathetic dystrophy following distal radius fracture after previous various treatments have failed.

Materials and methods

This comparative prospective study was designed for 64 patients of reflex sympathetic dystrophy developed following distal radius fracture, from January 2009 to December 2020 were enrolled in this study. This cohort of patient was given either four multiple subcutaneous platelet-rich plasma injections at weekly interval (n = 32) or two injections in a month with 15 days interval (n = 32). The primary outcome measure assessed with patient rated wrist evaluation questionnaire score. The secondary outcome was a visual analogue scale pain score. The final follow up was at 2 years. p ≤ 0.05 is considered statistically.

Results

The patient rated wrist evaluation score for usual and specific activities and EQ-VAS for pain level showed statistically significant greater improvement in group A (42 ± 21%) compared to group B (19 ± 24%), (p = 0.37). Patients also had improvement in wrist movements with no statistically significant differences in both groups. The standard difference in means of all three functional scores was almost similar between both groups A and B (standard difference in means = 0.032; 95% CI 0.236-0.830; p = 0.495), considered clinically meaningful.

Conclusion

This study results suggest autologous platelet-rich plasma injections seem to be safe, cost effective, efficacious algorithm treatment for reflex sympathetic dystrophy following distal radius fracture patients where previous treatments have failed.

Complex Regional Pain Syndrome in Cancer Cases: Current Knowledge and Perspectives

Background

Complex regional pain syndrome (CRPS) is a disabling painful disorder caused by many different and poorly understood mechanisms. It often affects the distal limbs and usually happens as consequence of a trauma. Its severity can remarkably affect patients' quality of life. When this painful complication happens in a cancer patient, the impact may be exponential. To date, there is limited knowledge of the surrounding circumstances of CRPS cases in this population.

Methods

We present two clinical cases of patients diagnosed with cancer-related pain presenting with symptoms and signs compatible with CRPS. In one case, CRPS was attributed to direct tumor nerve compression, and it responded successfully to an interventional pain procedure. The second case was associated with a Zoster infection in an immunocompromised cancer patient. Patient responded to multidisciplinary pain management strategies. Additionally, we conducted a literature review to investigate the coexistence of cancer pain and CRPS and suggest some pathophysiology mechanisms of action.

Results and Discussion

Literature reviewed and potential pathophysiology mechanisms are simultaneously explored in terms of classification, etiopathology, evidence, challenges, and future scientific directions.

Conclusion

Comorbid CRPS can impact negatively in cases of cancer pain by affecting their diagnosis and treatment. Further studies are necessary to elucidate how these two conditions present together and how they can be better addressed.

Mechanisms of complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is a chronic pain disorder characterized by a diverse array of symptoms, including pain that is disproportionate to the initial triggering event, accompanied by autonomic, sensory, motor, and sudomotor disturbances. The primary pathology of both types of CRPS (Type I, also known as reflex sympathetic dystrophy, RSD; Type II, also known as causalgia) is featured by allodynia, edema, changes in skin color and temperature, and dystrophy, predominantly affecting extremities. Recent studies started to unravel the complex pathogenic mechanisms of CRPS, particularly from an autoimmune and neuroimmune interaction perspective. CRPS is now recognized as a systemic disease that stems from a complex interplay of inflammatory, immunologic, neurogenic, genetic, and psychologic factors. The relative contributions of these factors may vary among patients and even within a single patient over time. Key mechanisms underlying clinical manifestations include peripheral and central sensitization, sympathetic dysregulation, and alterations in somatosensory processing. Enhanced understanding of the mechanisms of CRPS is crucial for the development of effective therapeutic interventions. While our mechanistic understanding of CRPS remains incomplete, this article updates recent research advancements and sheds light on the etiology, pathogenesis, and molecular underpinnings of CRPS.

Complex regional pain syndrome: advances in epidemiology, pathophysiology, diagnosis, and treatment

Complex regional pain syndrome (CRPS) is a rare pain disorder that usually occurs in a limb after trauma. The features of this disorder include severe pain and sensory, autonomic, motor, and trophic abnormalities. Research from the past decade has offered new insights into CRPS epidemiology, pathophysiology, diagnosis, and treatment. Early identification of individuals at high risk of CRPS is improving, with several risk factors established and some others identified in prospective studies during the past 5 years. Better understanding of the pathophysiological mechanisms of CRPS has led to its classification as a chronic primary pain disorder, and subtypes of CRPS have been updated. Procedures for diagnosis have also been clarified. Although effective treatment of CRPS remains a challenge, evidence-based integrated management approaches provide new opportunities to improve patient care. Further advances in diagnosis and treatment of CRPS will require coordinated, international multicentre initiatives.

Impact of different CRPS phenotypes and diagnostic criteria on quantitative sensory testing outcomes: systematic review and meta-analysis

OBJECTIVES

This review and meta-analysis evaluated the impact of diagnostic criteria and clinical phenotypes on quantitative sensory testing (QST) outcomes in patients with complex regional pain syndrome (CRPS).

METHODS

Eight databases were searched based on a previously published protocol. Forty studies comparing QST outcomes between CRPS-I vs II, warm vs cold CRPS, upper vs lower limb CRPS, males vs females, or using Budapest vs older IASP criteria were included.

RESULTS

Studies investigating QST differences between CRPS-I vs II (n = 4), between males vs females (n = 2), and between upper and lower limb CRPS (n = 2) showed no significant differences. Four studies compared QST outcomes in warm vs cold CRPS, showing heat hyperalgesia in warm CRPS, with thermal and mechanical sensory loss in cold CRPS. Although CRPS diagnosed using the Budapest criteria (24 studies) vs 1994 IASP criteria (13 studies) showed similar sensory profiles, there was significant heterogeneity and low quality of evidence in the latter.

CONCLUSIONS

Based on the findings of this review, classifying CRPS according to presence or absence of nerve lesion into CRPS-I and II, location (upper or lower limb) or according to sex might not be clinically relevant as all appear to have comparable sensory profiles that might suggest similar underlying mechanisms. In contrast, warm vs cold phenotypes exhibited clear differences in their associated QST sensory profiles. To the extent that differences in underlying mechanisms might lead to differential treatment responsiveness, it appears unlikely that CRPS-I vs II, CRPS location, or patient sex would prove useful in guiding clinical management.

Different Types of Pain in Complex Regional Pain Syndrome Require a Personalized Treatment Strategy

Complex regional pain syndrome (CRPS) is a debilitating painful state of an extremity that can develop after trauma. CRPS is diagnosed by the new International Association for the Study of Pain (IASP) diagnostic criteria for CRPS. The syndrome is characterized by continuing regional pain with abnormal sensory, motor, sudomotor, vasomotor, edema, and/or trophic signs. The clinical presentation of CRPS can be very heterogeneous because CRPS is a multi-mechanism syndrome. Therefore, mechanism-based subgroups have been suggested to personalize treatment for CRPS. Additionally, the presentation of symptom pain may also be able to identify different subgroups of CRPS. In this review, the types of pain recognized by the IASP-nociceptive, neuropathic, and nociplastic pain-will be discussed as possible subgroups for CRPS. Each pain type should be identified in CRPS patients, with a thorough history taking, physical examination, and diagnostic tests or (novel) biomarkers to optimize treatment effectiveness. Over the course of the syndrome, patients with CRPS probably experience more than one distinct pain type. Therefore, pain specialists should be alert to not only adjust their treatment if underlying pathophysiologic mechanisms tend to change but also to personalize the treatment of the associated type of pain in the CRPS patient.

Microbiota-Accessible Boron-Containing Compounds in Complex Regional Pain Syndrome

The microbiota-gut-brain axis has garnered increasing attention in recent years for its role in various health conditions, including neuroinflammatory disorders like complex regional pain syndrome (CRPS). CRPS is a debilitating condition characterized by chronic neuropathic pain, and its etiology and pathophysiology remain elusive. Emerging research suggests that alterations in the gut microbiota composition and function could play a significant role in CRPS development and progression. Our paper explores the implications of microbiota in CRPS and the potential therapeutic role of boron (B). Studies have demonstrated that individuals with CRPS often exhibit dysbiosis, with imbalances in beneficial and pathogenic gut bacteria. Dysbiosis can lead to increased gut permeability and systemic inflammation, contributing to the chronic pain experienced in CRPS. B, an essential trace element, has shown promise in modulating the gut microbiome positively and exerting anti-inflammatory effects. Recent preclinical and clinical studies suggest that B supplementation may alleviate neuropathic pain and improve CRPS symptoms by restoring microbiota balance and reducing inflammation. Our review highlights the complex interplay between microbiota, inflammation, and neuropathic pain in CRPS and underscores the potential of B as a novel therapeutic approach to target the microbiota-gut-brain axis, offering hope for improved management of this challenging condition.

Complex regional pain syndrome type II localized to the index finger. A case report translating scientific evidence into clinical practice

BACKGROUND

Complex regional pain syndrome type II (CRPS-II) is a rare condition associated with peripheral nervous system lesions. Its localized distribution in the fingers is unique, and its treatment is unclear.

CASE DESCRIPTION

A 56-year-old male presented to the emergency department with a saw-cut index finger injury with associated tendon and nerve injuries. After surgery, he was admitted to physical therapy (PT) with persistent pain, joint stiffness, allodynia, and trophic changes compatible with CRPS-II localized in the index finger. The diagnosis was confirmed after applying the Budapest Criteria, and PT was progressive and individualized according to the patient's needs, including graded motor imagery, mobilizations, exercises, and education.

OUTCOMES

After 12 weeks of PT, a clinically significant decrease in pain intensity and improvements in mobility and index finger and upper limb functionality was observed, reducing CRPS symptomatology.

DISCUSSION

This report provides information about a unique case of a localized form of CRPS-II. After reviewing the literature on clinical cases of both CRPS-II and localized forms of CRPS, we highlight that the clinical features of this patient and his positive therapeutic response support the importance of translating the scientific evidence on CRPS into clinical practice.

Clinical results of lumbar sympathetic blocks in lower limb complex regional pain syndrome using infrared thermography as a support tool

AIM

To describe the clinical outcomes for a group of complex regional pain syndrome patients using infrared thermography as an intraprocedural support tool when undertaking fluoroscopy-guided lumbar sympathetic blocks.

SUBJECTS

27 patients with lower limb complex regional pain syndrome accompanied by severe pain and persistent functional impairment.

METHODS

A series of three fluoroscopic-guided lumbar sympathetic blocks with local anesthetic and corticoids using infrared thermography as an intraprocedural support tool were performed. Clinical variables were collected at baseline, prior to each block, and one, three, and six months after blocks in a standardized checklist assessing each of the clinical categories of complex regional pain syndrome stipulated in the Budapest criteria.

RESULTS

23.75% of the blocks required more than one chance to achieve the desired thermal pattern and therefore to be considered as successful. A decrease in pain measured on a visual analogic scale was observed at all time points compared to pre-blockade data, but only 37% of the cases were categorized as responders, representing a ≥ 30% decrease in VAS, with the disappearance of pain at rest. An improvement of most of the clinical variables recorded was observed, such as tingling, edema, perception of thermal asymmetry, difference in coloring and sweating. There was a significant decrease of neuropathic pain and improvement of functional limitation. Logistic regression analysis showed the main variable to explain the probability of being a responder was immobilization time (odds ratio of 0.89).

CONCLUSION

A series of fluoroscopy-guided lumbar sympathetic blocks controlled by infrared thermography in the treatment of lower limb CRPS showed a responder rate of 37%.

A retrospective review of the management and outcomes of patients diagnosed with complex regional pain syndrome type II using electrodiagnostic findings

Objectives

The objective of this study was to assess the outcomes of the use of electrodiagnosis in the diagnosis and management of discrete nerve injuries in patients with complex regional pain syndrome (CRPS).

Design

This study is a secondary retrospective cohort analysis of patients diagnosed with CRPS from a single outpatient physical medicine and rehabilitation clinic and included all patients who had abnormal electrodiagnostic findings, in addition to CRPS.

Results

Sixty patients of 248 diagnosed with CRPS underwent electrodiagnosis, 41 of whom had abnormal electrodiagnostic findings indicating a discrete nerve injury. Only 51% of the 41 referrals had indicated the suspicion of a nerve injury. Nearly all patients had undergone physiotherapy. Forty-one percent responded to treatment with oral prednisone alone, 54% had a functional improvement after a combination of treatments including corticosteroids, and 5% improved with treatments that did not involve corticosteroids. Surgical interventions for nerve injuries were required for 34% of patients in the cohort. All surgeries involved the median or ulnar nerve, with the exception of one fibular nerve. After treatment, 39 of 41 patients had functional recoveries or better.

Conclusions

Electrodiagnosis can inform diagnosis of nerve injury and direct intervention including the need for surgical intervention. Electrodiagnosis should be considered for patients with initial signs of concomitant discrete nerve injury or with CRPS who are not responding to treatments because a nerve injury may be underlying.

What is Known Complex Regional Pain Syndrome (CRPS) is a poorly understood pain condition. CRPS has been divided into two subtypes, the second subtype involves a discrete nerve injury with pain that extends beyond the territory of the nerve injury.

What is New We observed that nerve injuries that may require surgical intervention are diagnosed just over half of the time upon initial assessment in patients with suspected CRPS. We observed that nerve injuries frequently required specifically directed interventions in place of or in conjunction with CRPS treatments. We suggest that electrodiagnosis is an important part of the triage protocol for CRPS II to reveal discrete nerve injuries that may be hidden. We recommend that electrodiagnosis be considered for patients with initial signs of concomitant discrete nerve injury or for CRPS patients who do not improve with medical therapies.

Interventions for treating pain and disability in adults with complex regional pain syndrome- an overview of systematic reviews

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic pain condition that usually occurs in a limb following trauma or surgery. It is characterised by persisting pain that is disproportionate in magnitude or duration to the typical course of pain after similar injury. There is currently no consensus regarding the optimal management of CRPS, although a broad range of interventions have been described and are commonly used. This is the first update of the original Cochrane review published in Issue 4, 2013.

OBJECTIVES

To summarise the evidence from Cochrane and non-Cochrane systematic reviews of the efficacy, effectiveness, and safety of any intervention used to reduce pain, disability, or both, in adults with CRPS.

METHODS

We identified Cochrane reviews and non-Cochrane reviews through a systematic search of Ovid MEDLINE, Ovid Embase, Cochrane Database of Systematic Reviews, CINAHL, PEDro, LILACS and Epistemonikos from inception to October 2022, with no language restrictions. We included systematic reviews of randomised controlled trials that included adults (≥18 years) diagnosed with CRPS, using any diagnostic criteria.  Two overview authors independently assessed eligibility, extracted data, and assessed the quality of the reviews and certainty of the evidence using the AMSTAR 2 and GRADE tools respectively. We extracted data for the primary outcomes pain, disability and adverse events, and the secondary outcomes quality of life, emotional well-being, and participants' ratings of satisfaction or improvement with treatment.  MAIN RESULTS: We included six Cochrane and 13 non-Cochrane systematic reviews in the previous version of this overview and five Cochrane and 12 non-Cochrane reviews in the current version. Using the AMSTAR 2 tool, we judged Cochrane reviews to have higher methodological quality than non-Cochrane reviews. The studies in the included reviews were typically small and mostly at high risk of bias or of low methodological quality. We found no high-certainty evidence for any comparison.  There was low-certainty evidence that bisphosphonates may reduce pain intensity post-intervention (standardised mean difference (SMD) -2.6, 95% confidence interval (CI) -1.8 to -3.4, P = 0.001; I2 = 81%; 4 trials, n = 181) and moderate-certainty evidence that they are probably associated with increased adverse events of any nature (risk ratio (RR) 2.10, 95% CI 1.27 to 3.47; number needed to treat for an additional harmful outcome (NNTH) 4.6, 95% CI 2.4 to 168.0; 4 trials, n = 181).  There was moderate-certainty evidence that lidocaine local anaesthetic sympathetic blockade probably does not reduce pain intensity compared with placebo, and low-certainty evidence that it may not reduce pain intensity compared with ultrasound of the stellate ganglion. No effect size was reported for either comparison. There was low-certainty evidence that topical dimethyl sulfoxide may not reduce pain intensity compared with oral N-acetylcysteine, but no effect size was reported. There was low-certainty evidence that continuous bupivacaine brachial plexus block may reduce pain intensity compared with continuous bupivacaine stellate ganglion block, but no effect size was reported. For a wide range of other commonly used interventions, the certainty in the evidence was very low and provides insufficient evidence to either support or refute their use. Comparisons with low- and very low-certainty evidence should be treated with substantial caution. We did not identify any RCT evidence for routinely used pharmacological interventions for CRPS such as tricyclic antidepressants or opioids.

AUTHORS' CONCLUSIONS

Despite a considerable increase in included evidence compared with the previous version of this overview, we identified no high-certainty evidence for the effectiveness of any therapy for CRPS. Until larger, high-quality trials are undertaken, formulating an evidence-based approach to managing CRPS will remain difficult. Current non-Cochrane systematic reviews of interventions for CRPS are of low methodological quality and should not be relied upon to provide an accurate and comprehensive summary of the evidence.

Prediction of the Efficacy of Lumbar Sympathetic Block in Patients with Lower Extremity Complex Regional Pain Syndrome Type 1 Based on the Sympathetic Skin Response

INTRODUCTION

Complex regional pain syndrome type 1 (CRPS-1) is prevalent after trauma, with intractable pain being the most prominent clinical symptom. The impact of sympathetic block on CRPS is unclear. The goal of this study was to explore the characteristics that predict successful symptom relief with lumbar sympathetic block (LSB) in patients with lower extremity CRPS-1.

METHODS

The study was designed as a prospective cohort study. Ninety-eight patients diagnosed with lower extremity CRPS-1 between March 2021 and March 2022 were enrolled as participants. All of the patients received two LSB treatments within a month. Sympthetic skin response (SSR) and numeric rating scale (NRS) were recorded before and after LSB treatment. The procedure was judged as a clinically positive response if the patients a 50% or greater reduction in NRS scores. Patients were divided into positive response and negative response groups after LSB treatment: LSB (+) and LSB (-), and the different characteristics and examination findings of the two groups of patients were compared. Furthermore, a multivariable logistic regression model was utilized to evaluate the predictors of successful symptom relief following LSB treatment.

RESULTS

A total of 43.9% (43/98) of patients experienced successful symptom relief, while 56.1% (55/98) had unsuccessful symptom relief. After LSB treatment of all subjects, the overall NRS score decreased, the SSR amplitude increased, and the SSR latency shortened in the affected extremity (P < 0.05). There was a significant difference in the change in SSR amplitude between the LSB (-) and LSB (+) groups (P = 0.000). A 12-month disease duration had an OR (odds ratio) of 4.477 (P = 0.009), and a 510-µV baseline SSR amplitude of the affected extremity had an OR of 7.508 (P = 0.000) in the multivariable analysis that included these explanatory variables.

CONCLUSIONS

Patients with lower extremity CRPS-1 can experience significant pain relief after LSB treatment. The predictors of successful symptom relief after LSB treatment were a baseline SSR amplitude of the affected extremity < 510 µV and a disease duration < 12 months.

TRIAL REGISTRATION

The study was registered in the Chinese Clinical Trial Registry (ID: ChiCTR2000037755, date of registration: September 4, 2020).

Multidisciplinary Management of Complex Regional Pain Syndrome (CRPS) Type 1 in the Hand and Wrist: A Case Report

Complex regional pain syndrome (CRPS) is a rare disorder that presents as a highly variable combination of intense regional pain, autonomic and vasomotor disturbances that are uncharacteristic of the inciting trauma or event. We report a 36-year-old male construction worker who presented to the orthopedic department status post crush injury to his hand, with acutely increasing right-hand pain, swelling, skin/hair changes, and dysfunction. Presentation changed over a course of 2-8 weeks, with CRPS becoming the eventual working diagnosis. Initial diagnoses were not made by occupational med, nor the urgent care, and definitive diagnosis was achieved in the orthopedic hand office via a thorough history and physical exam as well as imaging modalities including X-ray, CT, and MRI. A multidisciplinary approach involving aggressive hand therapy, anti-inflammatory agents, high-dose prednisone, Gabapentin, and over-the-counter vitamins and supplements was used in the treatment of this patient. This patient had a unique progression of his condition with respect to his carpus, demonstrating acute reduction of bone density on plain film. Stiffness ensued. This patient's condition was almost "missed" by the masking of the ulnar ossicle variant (os triangulare), and anatomical snuffbox pain on exam, in the face of initially "normal" X-rays. It is important for providers to recognize the clinical signs of complex regional pain syndrome, especially in the acute phase of crush injury, swelling, skin and hair changes, and stiffness, and to treat patients' symptoms with a variety of treatment options due to the marked variability of this condition. The patient has made a favorable recovery with some residual functional deficits, however, the patient stated that his quality of life has been restored despite his current stiffness.

A Pilot Study of Autonomic Function Screening Tests for Differentiating Complex Regional Pain Syndrome Type II and Traumatic Neuropathic Pain

Background and Objectives: One of the most challenging tasks in a clinical setting is to differentiate between complex regional pain syndrome (CRPS) type II and traumatic neuropathic pain (NeP). CRPS is characterized by several dysautonomic manifestations, such as edema, hyper/hypohidrosis, skin color change, and tachycardia. This study compared the outcomes of autonomic function screening tests in patients with CRPS type II and traumatic NeP for diagnostic differentiation. Materials and Methods: CRPS type II was diagnosed according to the Budapest research criteria, while NeP was diagnosed according to the updated grading system suggested by the International Association for the Study of Pain Special Interest Group on Neuropathic Pain in 2016. Twenty patients with CRPS type II and twenty-five with traumatic NeP were investigated. Results: Twelve patients with CRPS type II presented abnormal results for the quantitative sudomotor axon reflex test (QSART). Abnormal QSART results were more common in the CRPS type II group. Conclusions: Analysis of QSART combined with other ancillary tests can help in the differential diagnosis of CRPS type II and traumatic NeP if factors influencing abnormal QSART are sufficiently controlled.

Post-COVID-19 vaccination arm pain diagnosed as complex regional pain syndrome: A case report

As the vaccination efforts against the coronavirus disease-2019 (COVID-19) continue, more patients are likely to present with complications related to COVID-19 vaccination. We describe the first reported case of complex regional pain syndrome (CRPS), involving the upper extremities, that occurred after COVID-19 vaccination. The patient presented with acute-onset severe arm pain and swelling following vaccine administration. Based on the clinical, electrodiagnostic, and radionuclide three-phase bone scan findings, the patient was diagnosed with postvaccination CRPS. The COVID-19 vaccine possibly elicited an immune-mediated inflammatory response to the injected antigen in the patient, who was predisposed to CRPS due to inflammatory immunity. The COVID-19 vaccine elicited an immune-mediated inflammatory response to the injected antigen, resulting in CRPS following COVID-19 vaccination.

Atypical influence of biomechanical knowledge in Complex Regional Pain Syndrome-towards a different perspective on body representation

Part of the multifaceted pathophysiology of Complex Regional Pain Syndrome (CRPS) is ascribed to lateralized maladaptive neuroplasticity in sensorimotor cortices, corroborated by behavioral studies indicating that patients present difficulties in mentally representing their painful limb. Such difficulties are widely measured with hand laterality judgment tasks (HLT), which are also used in the rehabilitation of CRPS to activate motor imagery and restore the cortical representation of the painful limb. The potential of these tasks to elicit motor imagery is critical to their use in therapy, yet, the influence of the body's biomechanical constraints (BMC) on HLT reaction time, supposed to index motor imagery activation, is rarely verified. Here we investigated the influence of BMC on the perception of hand postures and movements in upper-limb CRPS. Patients were slower than controls in judging hand laterality, whether or not stimuli corresponded to their painful hand. Reaction time patterns reflecting BMC were mostly absent in CRPS and controls. A second experiment therefore directly investigated the influence of implicit knowledge of BMC on hand movement judgments. Participants judged the perceived path of movement between two depicted hand positions, with only one of two proposed paths that was biomechanically plausible. While the controls mostly chose the biomechanically plausible path, patients did not. These findings show non-lateralized body representation impairments in CRPS, possibly related to difficulties in using correct knowledge of the body's biomechanics. Importantly, they demonstrate the challenge of reliably measuring motor imagery with the HLT, which has important implications for the rehabilitation with these tasks.

Industry strategies to market opioids to children and women in the USA: a content analysis of internal industry documents from 1999 to 2017 released in State of Oklahoma v. Purdue Pharma, L.P. et al

OBJECTIVE

Identify advertising strategies used to market opioids to women and children.

DESIGN

Qualitative content analysis of internal pharmaceutical industry documents released in litigation, dated between 1999 and 2017.

SETTING

USA.

PARTICIPANTS

Opioid manufacturers (Janssen, Ortho-McNeil, Purdue, Teva (Actavis), Janus, Cephalon); women; children.

PRIMARY AND SECONDARY OUTCOME MEASURES

Advertising campaigns, industry executive statements regarding marketing goals METHODS: We examined ((DATASET) link: https://www.industrydocuments.ucsf.edu/drug/) documents released in State of Oklahoma v. Johnson & Johnson (2019) to identify marketing strategies and campaigns developed by opioid manufacturers that focused on children and women, as well as public records, including websites developed by manufacturers and their allies, to confirm whether marketing campaigns proposed in internal industry documents were implemented. Documents identified as relevant were coded for themes based on expectations drawn from previous research on marketing using internal industry documents, which included making emotional appeals and understating the risks of addiction.

RESULTS

We found that opioid manufacturers sought to recruit coaches and school nurses to encourage opioid use by children, developed unbranded initiatives suggesting adolescents ask providers for pain care medications, suggested that opioid use could reduce health risks associated with untreated pain among women and advocated to policy makers that women faced unmet needs for pain medication.

CONCLUSIONS

The USA strictly regulates direct marketing of medications but does not place the same restrictions on indirect marketing and unbranded campaigns, which encourage people to seek treatment without indicating the names of specific products. Opioid manufacturers in the early 21st century appear to have relied largely on unbranded campaigns for marketing, which they described externally as public health promotion and internally as a way to increase sales of opioids. The rapid increase in opioid use concomitant with these campaigns suggests that additional scrutiny of this kind of marketing may be needed in order to protect vulnerable groups.

Cold allodynia is correlated to paroxysmal and evoked mechanical pain in complex regional pain syndrome (CRPS)

OBJECTIVES

Mechanisms of complex regional pain syndrome (CRPS) are still debated. Identifying subgroups of patients have been attempted in the hope of linking clinical findings to possible mechanisms. The aim of the present study was to investigate whether subgroups of CRPS (based on quantitative sensory testing (QST)-results) differed with respect to different characteristics of pain like spontaneous ongoing or paroxysmal pain and mechanical dynamic allodynia.

METHODS

61 CRPS-patients (type 1 and 2) were examined clinically and with QST, in affected and contralateral extremity, with assessment of thresholds for warmth, cold and heat-and cold pain.

RESULTS

43 patients (20 men, 23 men) were diagnosed with CRPS 1 (70.5%) and 18 patients (8 women and 10 men) with CRPS 2 (29.5%). Three subgroups were defined based on thermal thresholds; A (thermal allodynia 22.9%), B (thermal hyposensitivity 37.3%), C (thermal allodynia and hyposensitivity 39.3%). Paroxysmal pain was more prevalent in patients with thermal allodynia (merging group A + C, 25/38-65.8%) compared to patients without thermal allodynia (group B, 5/23-21.7%) (p-value=0.00085).

CONCLUSIONS

We suggest that cold allodynia is based on hyper-excitability of very superficial skin nociceptors. The correlation between paroxysmal pain, allodynia to light touch and cold allodynia suggests that activity in those peripheral nociceptors can drive both, paroxysmal pain and spinal sensitization leading to stroke evoked allodynia. Mechanistically, the physical cold stimulus can unmask disease-related hyperexcitability by closure of temperature-sensitive potassium channels or induction of resurgent currents. Small fiber degeneration alone may not be the crucial mechanism in CRPS, nor explain pain.

Outcomes of Carpal Tunnel Release in Complex Regional Pain Syndrome/Reflex Sympathetic Dystrophy/Sudeck Disease Patients

BACKGROUND

The clinical features of classic carpal tunnel syndrome are well known. However, some patients who display atypical symptoms and signs of pain and dysesthesias in the hand, worsening of symptoms at night, and above all, inability to make a full fist, respond equally well to carpal tunnel release. This same clinical picture was shared by some patients labeled as having complex regional pain syndrome. Because of the poor outcome of complex regional pain syndrome patients with current regimens, the authors tested the hypothesis that carpal tunnel release could be effective on them. The purpose of this article is to report the outcome of carpal tunnel release in complex regional pain syndrome patients who presented the above signs and symptoms.

METHODS

Fifty-three patients with an average age of 55 years presenting the above cluster of symptoms were operated on. All were unilateral cases, had sustained trauma, and were treated for complex regional pain syndrome before referral for an average of 16 months. All patients underwent carpal tunnel release.

RESULTS

At a minimum of 6 months' follow-up, pain dropped 7.5 points on a numerical rating scale of 0 to 10 ( p < 0.001). Disabilities of the Arm, Shoulder and Hand scoring fell from 82 to 17 ( p < 0.001). Six patients had an unsatisfactory result.

CONCLUSIONS

Some patients with complex regional pain syndrome may respond successfully to a carpal tunnel release operation. Recognition of this possibility is crucial, as the symptoms and signs might lead the clinician away from the proper diagnosis and treatment.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Determinants of Complex Regional Pain Syndrome Type I among Radial Head Fracture Patients with Unilateral Arthroplasty

OBJECTIVE

This study aims to assess the proportions of complex regional pain syndrome type I (CRPS I) in radial head fracture patients undergoing unilateral arthroplasty and to explore associated factors.

METHODS

This is a prospective observational study. From March 2016 to May 2019, a total of 221 adult patients with radial head fracture patients were included in consecutive studies and completed the 1-year follow-up. All patients were treated by unilateral arthroplasty. At each follow-up visit, the visual analogue scale was used to measure patients' pain level. Occurrence of CRPS I, which was diagnosed by Budapest criteria, was the main outcome collected at baseline and the 1-, 3-, 6-, and 9-month follow-ups. The baseline data were collected before surgery and included demographic and clinical data. Independent t-tests and χ² tests were used as univariate analyses to compare the baseline data of patients with and without CRPS I. Multivariate analysis (Backword-Wald) was used to identify factors independently associated with CRPS I.

RESULTS

The proportion of CRPS I cases among radial head fracture patients undergoing unilateral arthroplasty was 11% (n = 24). A total of 19 (79%) patients were diagnosed with CRPS I within 1 month after surgery. Multivariable logistic regression analysis revealed that female gender (odds ratios [OR]: 1.537; 95% confidence interval [CI]: 1.138-2.072), age younger than 60 years (OR: 1.682; 95% CI: 1.246-2.267), moderate and severe Mayo Elbow Performance Score (MEPS) pain (OR: 3.229; 95% CI: 2.392-4.351) and anxiety (OR: 83.346; 95% CI: 61.752-112.320) were independently associated with CRPS I.

CONCLUSIONS

This exploratory study reported that the incidence of CRPS I developing after radial head arthroplasty was 11%. Female sex, younger age, moderate and severe MEPS pain and anxiety patients seems more likely to develop CRPS I.

Development of an Exoskeleton Platform of the Finger for Objective Patient Monitoring in Rehabilitation

This paper presents the application of an adaptive exoskeleton for finger rehabilitation. The system consists of a force-controlled exoskeleton of the finger and wireless coupling to a mobile application for the rehabilitation of complex regional pain syndrome (CRPS) patients. The exoskeleton has sensors for motion detection and force control as well as a wireless communication module. The proposed mobile application allows to interactively control the exoskeleton, store collected patient-specific data, and motivate the patient for therapy by means of gamification. The exoskeleton was applied to three CRPS patients over a period of six weeks. We present the design of the exoskeleton, the mobile application with its game content, and the results of the performed preliminary patient study. The exoskeleton system showed good applicability; recorded data can be used for objective therapy evaluation.

Relative Prevalence and Associated Factors of Complex Regional Pain Syndrome Type I in Patients with Radial Head Fractures Treated with Open Reduction and Internal Fixation: A Cross-Sectional Study

Objective

This cross-sectional study aimed to examine the incidence and associated factors of complex regional pain syndrome type I (CRPS I) in patients who underwent open reduction and internal fixation (ORIF) for radial head fractures.

Methods

The study enrolled 601 radial head fracture patients treated with ORIF, 523 of which completed the 1-year follow-up. The incidence of CRPS I in those patients was assessed using the Budapest criteria. Patients were then divided into 2 groups: patients with CRPS I (n = 28) and patients without CRPS I (n = 495). The patients' demographic and clinical data before the operation were prospectively collected by our team. Independent t-tests and χ² tests were used as univariate analyses to compare the demographic and clinical data between the two groups. Meanwhile, multivariate regression analysis was conducted to identify the associated risk factors for CRPS I.

Results

The incidence of CRPS I in patients with radial head fractures treated with ORIF was 5.5% during the first year following surgery. Significant differences were observed in age, gender, type of trauma, modified Mason Classification, and depressive personality disorders. The logistic regression analysis revealed that the female gender, modified Mason type III fractures, and depressive patients were significantly more likely to develop CRPS I (p=0.021, 0.023, and 0.025, respectively).

Conclusions

The incidence of CRPS I among radial head fracture patients undergoing ORIF was 5.5%. In addition, early detection of CRPS I and providing adequate intervention will likely result in greater benefits for those patients.

Physiotherapy for pain and disability in adults with complex regional pain syndrome (CRPS) types I and II

BACKGROUND

Complex regional pain syndrome (CRPS) is a painful and disabling condition that usually manifests in response to trauma or surgery and is associated with significant pain and disability. CRPS can be classified into two types: type I (CRPS I) in which a specific nerve lesion has not been identified and type II (CRPS II) where there is an identifiable nerve lesion. Guidelines recommend the inclusion of a variety of physiotherapy interventions as part of the multimodal treatment of people with CRPS. This is the first update of the review originally published in Issue 2, 2016.

OBJECTIVES

To determine the effectiveness of physiotherapy interventions for treating pain and disability associated with CRPS types I and II in adults.

SEARCH METHODS

For this update we searched CENTRAL (the Cochrane Library), MEDLINE, Embase, CINAHL, PsycINFO, LILACS, PEDro, Web of Science, DARE and Health Technology Assessments from February 2015 to July 2021 without language restrictions, we searched the reference lists of included studies and we contacted an expert in the field. We also searched additional online sources for unpublished trials and trials in progress.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of physiotherapy interventions compared with placebo, no treatment, another intervention or usual care, or other physiotherapy interventions in adults with CRPS I and II. Primary outcomes were pain intensity and disability. Secondary outcomes were composite scores for CRPS symptoms, health-related quality of life (HRQoL), patient global impression of change (PGIC) scales and adverse effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened database searches for eligibility, extracted data, evaluated risk of bias and assessed the certainty of evidence using the GRADE system.

MAIN RESULTS

We included 16 new trials (600 participants) along with the 18 trials from the original review totalling 34 RCTs (1339 participants). Thirty-three trials included participants with CRPS I and one trial included participants with CRPS II. Included trials compared a diverse range of interventions including physical rehabilitation, electrotherapy modalities, cortically directed rehabilitation, electroacupuncture and exposure-based approaches. Most interventions were tested in small, single trials. Most were at high risk of bias overall (27 trials) and the remainder were at 'unclear' risk of bias (seven trials). For all comparisons and outcomes where we found evidence, we graded the certainty of the evidence as very low, downgraded due to serious study limitations, imprecision and inconsistency. Included trials rarely reported adverse effects. Physiotherapy compared with minimal care for adults with CRPS I One trial (135 participants) of multimodal physiotherapy, for which pain data were unavailable, found no between-group differences in pain intensity at 12-month follow-up. Multimodal physiotherapy demonstrated a small between-group improvement in disability at 12 months follow-up compared to an attention control (Impairment Level Sum score, 5 to 50 scale; mean difference (MD) -3.7, 95% confidence interval (CI) -7.13 to -0.27) (very low-certainty evidence). Equivalent data for pain were not available. Details regarding adverse events were not reported. Physiotherapy compared with minimal care for adults with CRPS II We did not find any trials of physiotherapy compared with minimal care for adults with CRPS II.

AUTHORS' CONCLUSIONS

The evidence is very uncertain about the effects of physiotherapy interventions on pain and disability in CRPS. This conclusion is similar to our 2016 review. Large-scale, high-quality RCTs with longer-term follow-up are required to test the effectiveness of physiotherapy-based interventions for treating pain and disability in adults with CRPS I and II.

Complex Regional Pain Syndrome of the Knee after Conventional Radiofrequency Ablation of the Genicular Nerves Treated Successfully with Dorsal Root Ganglion Stimulation: A Case Report

Background

Radiofrequency (RF) treatment of the genicular nerves offers pain relief in patients suffering from chronic knee pain including persistent post‐surgical knee pain (PPSP). We present the first case report of the development of complex regional pain syndrome (CRPS) in a chronic knee pain patient after an RF ablation of the genicular nerves that was successfully treated with dorsal root ganglion (DRG) stimulation.

Case Presentation

The patient developed increased pain, sympathetic and dysmorphic changes of the index knee 10 weeks after RF treatment for PPSP. Diagnosis of CRPS type II was made using positive clinical findings and the Budapest diagnostic tool. Laboratory workup and PET‐CT were negative. The patient was refractory to usual care and she was treated successfully with dorsal ganglion root stimulation.

Conclusions

Complex regional pain syndrome is a possible complication of RF ablation of the genicular nerves in patients with chronic knee pain, and DRG stimulation may be a treatment option. Physicians should be aware of this complication, especially when patients have a medical history of CRPS.

Immunoregulatory Effect of Preventive Supplementation of Omega-3 Fatty Acid in a Complex Regional Pain Syndrome Type I Model in Mice

Objective

Complex regional pain syndrome (CRPS) is usually triggered by trauma or a surgical procedure, and it typically becomes an established one after an intense inflammatory process with chronic pain and edema as the main symptoms. Available treatments for CRPS have low efficacy. This study aimed to evaluate the clinical and immunoregulatory effects of omega-3 polyunsaturated fatty acid (PUFA) supplementation on paw edema and anti- and pro-inflammatory cytokines and macrophage phenotypes in the chronic post-ischemia pain (CPIP) preclinical model of CRPS-Type I.

Methods

Female Swiss mice were supplemented with omega-3, corn oil, or saline and then submitted to the CPIP model of ischemia/reperfusion (I/R) injury. Supplementation was carried out for 30 days prior to and up to 2 or 15 days after the induction of CPIP, according to experimental protocols. The supplementation protocol included 1,500 mg/kg of omega-3 or corn oil through an intragastric route (gavage). Paw edema, interleukin- (IL-) 4, IL-10, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor (TNF) were then measured in the paw skin and muscle by enzyme-linked immunosorbent assay (ELISA), and macrophage phenotypes (M1 and M2) assessed in the paw muscle by Western blotting.

Results

The CPIP model induced an increase in paw thickness up to 72 h post-I/R. Mice supplemented with omega-3 compared to the saline group displayed reduced edema but neither altered skin IL-4 or skin and muscle TGF-β1, TNF, and MCP-1 concentrations, nor did they exhibit significantly altered muscle macrophage phenotype on the 2nd-day post-CPIP. However, omega-3 supplementation reversed the I/R-related reduction in IL-4 in the paw muscle compared to groups supplemented with saline and corn oil. Furthermore, omega-3 promoted the reduction of IL-10 levels in the paw skin, compared to animals with lesions supplemented with saline, until the 2nd-day post-CPIP. On the 15th day post-CPIP, IL-10 was significantly increased in the muscle of animals supplemented with omega-3 compared to the saline group.

Conclusion

The results suggest that omega-3 PUFA supplementation has anti-inflammatory effects in the CPIP model of CRPS-Type I, significantly reducing paw edema and regulating concentrations of anti-inflammatory cytokines, including IL-4 and IL-10.

Characteristics of Patients With Complex Limb Pain Evaluated Through an Interdisciplinary Approach Utilizing Magnetic Resonance Neurography

Patients with persistent complex limb pain represent a substantial diagnostic challenge. Physical exam, and tests such as nerve conduction, are often normal even though the patient suffers from severe pain. In 2015, we initiated a team-based approach to evaluate such patients. The approach included physicians from several specialties (Anesthesiology/Pain Medicine, Radiology, Plastic Surgery, Neurosurgery) combined with the use of advanced imaging with Magnetic Resonance Neurography (MRN). This preliminary case series discusses MRN findings identified in patients with previously difficult-to-diagnose peripheral limb pain and describes how this combination of approaches influenced our diagnosis and treatment plans. We extracted demographics, patient characteristics, presenting features, diagnostic tests performed, treatments provided, referral diagnosis and the diagnosis after interdisciplinary team evaluation from patient charts. We evaluated MRN and electrodiagnostic studies (EDX) ability to identify injured nerves. We compared abnormal findings from these diagnostics to patient reported outcome after ultrasound-guided nerve block. A total of 58 patients, 17 males and 41 females, were identified. The majority of patients presented with lower extremity pain (75%) and had prior surgery (43%). The most commonly identified abnormality on MRN was nerve signal alteration on fluid sensitive sequences, followed by caliber change and impingement. Comparing the outcome of diagnostic nerve blocks with abnormal nerve findings on MRN or EDX, we found that MRN had a sensitivity of 67% and specificity of 100% while for EDX it was 45 and 0%, respectively. After interdisciplinary discussion and imaging review, a more specific diagnosis was produced in 78% of evaluated cases opening up additional treatment pathways such as nerve-targeted surgery, which was performed in 36% cases. This descriptive case series demonstrates that a majority of patients evaluated by our team for complex limb pain were women with lower extremity pain resulting from surgery. In addition, an interdisciplinary team evaluation and the use of the moderately sensitive but highly specific MRN imaging modality resulted in a change in diagnosis for a majority of patients with complex limb pain. Future studies investigating patient outcomes after diagnosis change are currently underway based on the findings of this preliminary study.

Management of pain using magnesium sulphate: A narrative review

Pain is one of the most complex and unpleasant sensory and emotional human experiences. Pain relief continues to be a major medical challenge. The application of systemic opioid and regional analgesia techniques has facilitated a decrease in the occurrence and gravity of pain. Magnesium has an evolving role in pain management. Magnesium sulphate (MgSO4), the pharmacological form of magnesium, is a physiological voltage-dependent blocker of N-methyl-D-aspartate (NMDA)-coupled channels. In terms of its antinociceptive role, magnesium blocks calcium influx, which inhibits central sensitization and decreases preexisting pain hypersensitivity. These properties have encouraged the research of magnesium as an adjuvant agent for intra- and post-operative analgesia. Moreover, the mentioned magnesium impacts are also detected in patients with neuropathic pain. Intravenous magnesium sulphate, followed by a balanced analgesia, decreases opioid consumption. This review has focused on the existing evidence concerning the role of magnesium sulphate in pain management in situations including neuropathic pain, postherpetic neuralgia, trigeminal neuralgia, migraine, and post-operative pain. Additional studies are required to improve the use of magnesium sulphate for pain to increase the quality of life of patients.

Pain, disability, and lifestyle: Patients with complex regional pain syndrome compared to chronic musculoskeletal pain - a retrospective analysis

BACKGROUND

Complex regional pain syndrome (CRPS) is an orphan disease occurring as a complication after trauma. Due to its acute onset and the typical clinical presentation of the inflammatory and autonomous signs, it is an eye-catching chronic pain disease affecting also young and working people. In social media and the internet, high pain severity and unfavorable prognosis is often empathized.

METHODS

Here, we compared epidemiological, pain and lifestyle factors of 223 CPRS patients from the "ncRNAPain" cohort with 255 patients with chronic musculoskeletal pain (MSK). MSK patients were recruited at the beginning of a multimodal pain therapy program. We searched for factors predicting pain intensity.

RESULTS

Both chronic pain diseases affected women in middle age. Patients with MSK were more obese, drank more alcohol and were less educated (Pearson Chi-square Test or Mann-Whitney/U-Test). Both groups smoked more than healthy people in the OECD (Organization for Economic Cooperation and Development). Mann-Whitney/U-Test confirmed that CRPS patients did not have more severe pain and did not suffer more from pain-related disability than patients with MSK. CRPS patients also had less psychiatric comorbidities. Multiple linear regression analysis revealed that group assignment, depressive characteristics, body mass index, average alcohol consumption and smoking predicted higher pain ratings, while disease duration, anxiety symptoms or gender had no influence on pain intensity.

CONCLUSION

In summary our study supports a more optimistic view on pain in CRPS patients in comparison to MSK and identifies lifestyle factors which might contribute to the pathophysiology like smoking and drinking. Important next steps are the identification of CRPS patients at risk for chronification or - vice versa - with protective factors for pain resolution.

Determining the credibility, accuracy and comprehensiveness of websites educating consumers on complex regional pain syndrome accessible in Australia: a systematic review

Complex regional pain syndrome (CRPS) is a distressing and disabling pain condition. Many people with CRPS and the health professionals who treat them seek information about the condition via the Internet. The credibility, accuracy and comprehensiveness of online CRPS information remains unknown. The aim of this study was to determine the credibility, accuracy and comprehensiveness of information presented on freely accessible websites that aim to educate people about CRPS. Keyword searches were conducted on the Australian Google site, with 'trustworthy' websites included and critically appraised. Primary outcomes were recognised metrics of credibility (JAMA benchmark credibility criteria) and website accuracy (according to European CRPS guidelines). Comprehensiveness was assessed using the proportion of European CRPS guidelines covered by the websites. In all, 30 websites with 819 recommendations were critically appraised. Five (17%) websites met all credibility criteria; of the recommendations, 349 (43%) were accurate, 252 (31%) were inaccurate and 218 (26%) were unclear. For comprehensiveness, an average of 17% of general guidelines, 15% of therapeutic guidelines and 6% of medication/supplement guidelines were covered. Online information about CRPS available to Australians has low credibility, accuracy and comprehensiveness. Many website recommendations are inaccurate or unclear, and many websites endorse inappropriate treatments. There is an urgent need for accurate and comprehensive sources of CRPS information online.

Effectiveness of prednisolone in complex regional pain syndrome treatment: A systematic narrative review

BACKGROUND

Many patients with complex regional pain syndrome (CRPS) experience refractory pain with severe restrictions in the activities of daily living. Oral prednisolone is commonly used to treat these patients.

PURPOSE

To review previous studies assessing the effects of prednisolone in CRPS patients.

METHODS AND MATERIALS

Articles published from January 1, 1980 to July 23, 2021 in the PubMed database were searched using the following key phrases: (prednisolone OR corticosteroid OR steroid) AND (complex regional pain syndrome OR reflex sympathetic dystrophy OR shoulder-hand syndrome OR causalgia). Specifically, we included those articles in which oral prednisolone or corticosteroids were used to control the CRPS symptoms.

RESULTS

In total, 11 articles were included, comprising 3 randomized trials, 5 single-arm prospective observational studies, and 3 retrospective studies. Nearly all previous studies reported that oral prednisolone can effectively control the CRPS symptoms. Moreover, though 30-100 mg/day of oral prednisolone was initially administered in these studies, 30 mg/day was also found to be effective in controlling the symptoms. Although prednisolone was usually administered for 1-3 months, short-term treatment for 1-2 weeks was also reportedly effective. Furthermore, only 0%-30% of the patients in these studies had minor side effects after prednisolone treatment.

CONCLUSIONS

Our review showed that prednisolone may be effective in alleviating the CRPS symptoms. To determine higher levels of evidence, a full systematic review with more highly qualified studies, such as randomized controlled trials, should be conducted in the future.

Complex Regional Pain Syndrome. A Comprehensive Review on Neuroplastic Changes Supporting the Use of Non-invasive Neurostimulation in Clinical Settings

Background: Complex regional pain syndrome (CRPS) is a rare debilitating disorder characterized by severe pain affecting one or more limbs. CRPS presents a complex multifactorial physiopathology. The peripheral and sensorimotor abnormalities reflect maladaptive changes of the central nervous system. These changes of volume, connectivity, activation, metabolism, etc., could be the keys to understand chronicization, refractoriness to conventional treatment, and developing more efficient treatments. Objective: This review discusses the use of non-pharmacological, non-invasive neurostimulation techniques in CRPS, with regard to the CRPS physiopathology, brain changes underlying chronicization, conventional approaches to treat CRPS, current evidence, and mechanisms of action of peripheral and brain stimulation. Conclusion: Future work is warranted to foster the evidence of the efficacy of non-invasive neurostimulation in CRPS. It seems that the approach has to be individualized owing to the integrity of the brain and corticospinal function. Non-invasive neurostimulation of the brain or of nerve/muscles/spinal roots, alone or in combination with conventional therapy, represents a fertile ground to develop more efficient approaches for pain management in CRPS.

Alcohol amplifies cingulate cortex signaling and facilitates immobilization-induced hyperalgesia in female rats

Complex Regional Pain Syndrome (CRPS) is a musculoskeletal pain condition that often develops after limb injury and/or immobilization. Although the exact mechanisms underlying CRPS are unknown, the syndrome is associated with central and autonomic nervous system dysregulation and peripheral hyperalgesia symptoms. These symptoms also manifest in alcoholic neuropathy, suggesting that the two conditions may be pathophysiologically accretive. Interestingly, people assigned female at birth (AFAB) appear to be more sensitive to both CRPS and alcoholic neuropathy. To better understand the biobehavioral mechanisms underlying these conditions, we investigated a model of combined CRPS and alcoholic neuropathy in female rats. Animals were pair-fed either a Lieber-DeCarli alcohol liquid diet or a control diet for ten weeks. CRPS was modeled via unilateral hind limb cast immobilization for seven days, allowing for the other limb to serve as a within-subject control for hyperalgesia measures. To investigate the role of circulating ovarian hormones on pain-related behaviors, half of the animals underwent ovariectomy (OVX). Using the von Frey procedure to record mechanical paw withdrawal thresholds, we found that cast immobilization and chronic alcohol drinking separately and additively produced mechanical hyperalgesia observed 3 days after cast removal. We then examined neuroadaptations in AMPA GluR1 and NMDA NR1 glutamate channel subunits, extracellular signal-regulated kinase (ERK), and cAMP response element-binding protein (CREB) in bilateral motor and cingulate cortex across all groups. Consistent with increased pain-related behavior, chronic alcohol drinking increased GluR1, NR1, ERK, and CREB phosphorylation in the cingulate cortex. OVX did not alter any of the observed effects. Our results suggest accretive relationships between CRPS and alcoholic neuropathy symptoms and point to novel therapeutic targets for these conditions.

Complex Region Pain Syndrome Following Shoulder Surgery

Purpose

To describe the clinical features, treatment, and outcomes in patients with complex region pain syndrome (CRPS) following shoulder surgeries.

Methods

Three patients were diagnosed with CRPS according to the Budapest criteria. Patients were followed up prospectively at regular intervals for a minimum of 2 years. Demographic data, clinical symptoms, physical examination findings, treatment received, and outcomes were collected and reported.

Results

The minimum time interval between surgery and diagnosis was 3 weeks (average, 8 weeks). The index procedures included 2 arthroscopic rotator cuff repairs and 1 open Latarjet. Neurologic pain, muscle spasms, hand and wrist swelling, and joint stiffness were seen in the shoulder, wrist, and hand, but the elbow was spared in all patients. Despite the use of multimodal treatment modalities, the symptoms were refractory to treatment for prolonged periods (range, 6-12 months). Hand and wrist symptoms took an average of 4 months longer than shoulder symptoms to improve. At the latest follow-up (range, 24-26 months), varying degrees of residual hand dysfunction, pain, and inability to make a fist or fully extend the fingers were noted in all 3 patients.

Conclusions

CPRS type 1 following shoulder surgery is a disabling condition with a long-protracted clinical course. CRPS can present as early as few weeks after shoulder surgery, with symptoms of neuropathic pain, spasm, and stiffness affecting the entire upper-extremity joints except the elbow. CRPS symptoms resolve earlier in the shoulder compared with the wrist and hand, with pain improving first, followed by recovery of motion and function. Residual stiffness affecting grip function is last to recover and can present up to 2 years after onset of symptoms. Although prompt recognition and multimodal approach are considered the mainstay of treatment, there is no gold standard treatment modality that can reproducibly alter the natural history of CRPS.

Level of Evidence

IV, therapeutic case series.

Bier block as a successful management of a patient with intractable complex regional pain syndrome (CRPS) type 1: A case report

Bier block was successful in the pain management of complex regional pain syndrome (CRPS) type 1.

Intramuscular neridronate for the treatment of complex regional pain syndrome type 1: a randomized, double-blind, placebo-controlled study

Background:

Complex regional pain syndrome type-1 (CRPS-1) is a severely disabling painful disease challenging to treat. This multicenter, randomized, double-blind placebo-controlled trial examined the efficacy of intramuscular (i.m.) neridronate in CRPS-1 patients.

Methods:

A total of 78 patients diagnosed with CRPS-1 (aged 59.5 ± 10.3, 66.7% female) were randomly assigned to 25 mg (i.m.) neridronate (N = 41) given once daily for 16 consecutive days or placebo control (N = 37). Efficacy was assessed after 30 days using a visual analogue scale (VAS) pain score and the number of patients achieving ⩾50% reduction in VAS score. Change in clinical signs and symptoms, quality of life (QoL) using Short Form Health Survey (SF-36) and the McGill Pain Questionnaire were also assessed.

Results:

After 30 days, VAS score decreased significantly to a greater extent in neridronate-treated patients versus placebo (31.9 ± 23.3 mm versus 52.3 ± 27.8 mm, p = 0.0003). Furthermore, the proportion of patients achieving a VAS reduction of ⩾50% was greater in the neridronate group (65.9% versus 29.7%, p = 0.0017). Clinical signs and symptoms were improved significantly in the neridronate group versus placebo for edema (72.5% versus 79.9%, p = 0.03), pain during motion (70% versus 83.3%, p = 0.0009), allodynia (20% versus 63.3%, p = 0.0004), and hyperalgesia (20% versus 56.7%, p = 0.0023). Whereas no difference was observed for QoL measures using the SF-36 questionnaire, three of the four pain variables using the McGill Pain Questionnaire improved significantly in the neridronate group. No serious drug-related adverse events were reported during the study.

Conclusion:

In patients with acute CRPS-1, i.m. injections of 25 mg neridronate were associated with clinically relevant benefit compared with placebo controls.

Trial registration:

EU Clinical Trials Register: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2014-001156-28

Possible Therapeutic Options for Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) describes an array of painful conditions that are characterized by continuing regional pain. CRPS comprises severe and inappropriate pain in cases of complete recovery after trauma. Research on the pharmacological treatment of CRPS, however, has not been well investigated. In this study, we compared the pain relief effects of different drugs (URB597, pyrrolidine dithiocarbamate, and hydralazine) in a rat model of chronic post-ischemic pain-induced CRPS. After drug injection, CRPS-induced mechanical allodynia was significantly recovered. After three repetitive drug injections, mechanical sensitivity generally improved as hyper-nociception subsided. Reduced Nav1.7 expression at dorsal root ganglions (DRGs) was observed in the drug treatment groups. Neural imaging analysis revealed decreased neural activity for each drug treatment, compared to vehicle. In addition, treatments significantly reduced IL-1β, IL-6, and TNFα expression in DRGs. These results indicated that drugs could reduce the expression of inflammatory factors and alleviate the symptoms of chronic post-ischemic pain-induced CRPS.

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

The challenge of recognizing severe pain and autonomic abnormalities for early diagnosis of CRPS

OBJECTIVES

Complex regional pain syndrome (CRPS) is a disabling usually post-traumatic pain condition. International guidelines emphasize early diagnosis for treatment and improved outcome. Early intense and persistent pain along with features of autonomic dysfunction in the first week's post-injury are early warning signs for development of CRPS. We have previously reported a delayed diagnosis of CRPS. The main purpose of the present study was to investigate possible causes of a delayed diagnosis, with a special focus of recognition of risk factors.

METHODS

A total of 52 CRPS 1 (without detectable nerve damage) and CRPS 2 (with evidence of nerve lesion) patients were included in the study. When examined at OUS-Rikshospitalet, we retrospectively asked the patients on the development of pain and autonomic abnormalities from the time of the eliciting injury, performed a thorough clinical investigation with an emphasis on signs of autonomic failure and compared symptoms and clinical findings with such information in previous medical records. We also evaluated symptoms and signs according to the type of injury they had suffered.

RESULTS

Of a total of 52 patients (30 women and 22 men, mean age 39.0 years at the time of injury), 34 patients had CRPS type 1 (65.4%) and 18 CRPS type 2 (34.6%), 25 patients with pain in the upper and 27 in the lower extremity. A total of 35 patients (67.3%) were diagnosed with CRPS (following mean 2.1 years) prior to the investigation at OUS-Rikshospitalet (mean 4.86 years following injury). Mean time from injury to diagnosis was 33.5 months (SD 30.6) (2.8 years) for all patients. In retrospect, all 17 patients first diagnosed at OUS met the CRPS diagnosis at an earlier stage. All patients retrospectively reported intense pain (numeric rating scale > 7) from the time of injury with a large discrepancy to previous medical records which only stated intense pain in 29.4% of patients with CRPS type 1 and 44.4% of patients with CRPS type 2 within the first four months. While the patients reported an early onset of autonomic dysfunction, present in 67.3 and 94.2% of the patients within one week and one month, respectively, reports of autonomic abnormalities within the first four months was far less (maximum in 51.7% of patients with CRPS type 1 and in 60% in CRPS 2). In 10 patients with CRPS type 1, no symptom nor sign of autonomic abnormalities was reported.

CONCLUSIONS

We still find a significant delay in the diagnosis of CRPS. There is a large discrepancy between both self-reporting of intense, disproportionate pain, as well as symptoms of autonomic abnormalities from the time of injury, and documentation in previous medical records. Our findings suggest a lack of awareness of risk factors for the development of CRPS, such as early intense pain and autonomic abnormalities without recovery, contributing to delayed diagnosis. The present results suggest causes of delayed CRPS-diagnosis. An increased attention to early warning signs/risk factors may improve diagnosis of CRPS.

Implications of the putamen in pain and motor deficits in complex regional pain syndrome

Complex regional pain syndrome (CRPS) develops after-limb injury, with persistent pain and deficits in movement frequently co-occurring. The striatum is critical for mediating multiple mechanisms that are often aberrant in CRPS, which includes sensory and pain processing, motor function, and goal-directed behaviors associated with movement. Yet, much remains unknown with regards to the morphological and functional properties of the striatum and its subregions in this disease. Thus, we investigated 20 patients (15 female, age 58 ± 9 years, right-handed) diagnosed with chronic (6+ months of pain duration) CRPS in the right hand and 20 matched, healthy controls with anatomical and resting-state, functional magnetic resonance imaging. In addition, a comprehensive clinical and behavioral evaluation was performed, where each participant's pain, motor function, and medical history were assessed. Complex regional pain syndrome patients harbored significant abnormalities in hand coordination, dexterity, and strength. These clinical pain- and movement-related findings in CRPS patients were concomitant with bilateral decreases in gray matter density in the putamen as well as functional connectivity increases and decreases among the putamen and pre-/postcentral gyri and cerebellum, respectively. Importantly, higher levels of clinical pain and motor impairment were associated with increased putamen-pre-/postcentral gyri functional connectivity strengths. Collectively, these findings suggest that putaminal alterations, specifically the functional interactions with sensorimotor structures, may underpin clinical pain and motor impairment in chronic CRPS patients.

Of mice, microglia, and (wo)men: a case series and mechanistic investigation of hydroxychloroquine for complex regional pain syndrome

Introduction

Complex regional pain syndrome (CRPS) is a condition that occurs after minor trauma characterized by sensory, trophic, and motor changes. Although preclinical studies have demonstrated that CRPS may be driven in part by autoinflammation, clinical use of immune-modulating drugs in CRPS is limited. Hydroxychloroquine (HCQ) is a disease-modifying antirheumatic drug used to treat malaria and autoimmune disorders that may provide benefit in CRPS.

Objectives

To describe the use of HCQ in patients with refractory CRPS and investigate possible mechanisms of benefit in a mouse model of CRPS.

Methods

We initiated HCQ therapy in 7 female patients with refractory CRPS undergoing treatment at the Stanford Pain Management Center. We subsequently undertook studies in the mouse tibial fracture-casting model of CRPS to identify mechanisms underlying symptom reduction. We evaluated behavior using mechanical allodynia and spinal cord autoinflammation by immunohistochemistry and enzyme-linked immunosorbent assay.

Results

We treated 7 female patients with chronic, refractory CRPS with HCQ 200 mg twice daily for 2 months, followed by 200 mg daily thereafter. Two patients stopped HCQ secondary to lack of response or side effects. Overall, HCQ significantly improved average numerical rating scale pain from 6.8 ± 1.1 before HCQ to 3.8 ± 1.9 after HCQ treatment. In the tibial fracture-casting mouse model of CRPS, we observed reductions in allodynia, paw edema, and warmth following daily HCQ treatment starting at 3 weeks after injury. Spinal cord dorsal horn microglial activation and cytokine levels were also reduced by HCQ treatment.

Conclusion

Together, these preclinical and clinical results suggest that HCQ may benefit patients with CRPS at least in part by modulating autoinflammation and support further investigation into the use of HCQ for CRPS.

Complex Regional Pain Syndrome Caused by an Axillary Lipoma

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy syndrome, is a rare chronic neuro-inflammatory pain condition, which can follow a soft-tissue, bone (type I), or nerve injury (type II) that can be severe and often lasts longer than the original tissue damage. Lipomas impinging on the brachial plexus are rare. To date, there have been no documented cases of CRPS caused by a benign tumor. Here, we report a rare case of CRPS caused by surgical removal of a left axillary lipoma impinging on the brachial plexus. The patient presented with neuropathic pain and hyperalgesia of the left arm, in a non-dermatomal pattern, and pain out of proportion to touch and painful stimulus. Persistent CRPS continued to occur post-operatively for one year without significant change in her pain characteristics. CRPS following elective or emergent surgery to the extremities can pose significant complications to recovery and post-operative care. This condition can be induced through surgery or trauma, which can complicate recovery, impair motor functionality, and cause debilitating pain. Treatment modalities and pathogenesis for CRPS remain obscure and limited, which leads to wide misdiagnosis. Our case highlights the importance of considering CRPS when evaluating differential diagnoses for pre- and post-operative conditions affecting the upper and lower extremities.

Intervention Using Body Shadow to Evoke Loading Imagery in a Patient with Complex Regional Pain Syndrome in the Foot: A Case Report

We present the case of a female patient who developed complex regional pain syndrome (CRPS) after a right-foot injury. The patient had pain from the right knee to the toes and showed severe disgust at the appearance of the affected limb. Consequently, the affected limb was not fully loaded, and the patient had difficulty walking. General interventions, such as mirror therapy, were attempted, but the effect was limited. We hypothesized that this was due to the disgust toward the affected limb, and we implemented a body-shadow intervention that we developed. This reduced the disgust for the affected limb and improved pain, but neither changed the anticipated pain of loading the affected limb nor improved the patient’s walking ability. The reason for this was considered to be that the previous interventions using the body shadow utilized the third-person perspective, denoting that the image of the load sensation on the sole of the foot during walking was insufficient; therefore, we attempted a first-person body-shadow intervention. The results showed improvement in the patient’s walking ability. In CRPS of the foot, it is important to use interventions that evoke images of loading without causing anticipatory pain, pointing to the effectiveness of body-shadow interventions.

Targeted muscle reinnervation at the time of amputation in the management of complex regional pain syndrome of the lower extremity

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic, posttraumatic condition defined by severe pain and sensorimotor dysfunction. In cases of severe CRPS, patients request amputation, which may cause phantom limb pain (PLP) and residual limb pain (RLP). Targeted muscle reinnervation (TMR) reduces the risk of PLP and RLP. This report describes the use of TMR at the time of amputation in a series of patients with CRPS.

PATIENTS AND METHODS

Four patients (ages 38-71 years) underwent TMR at the time of amputation for CRPS between April 2018 and January 2019. Three patients had a history of trauma and surgery to the affected limb. All patients attempted pharmacologic and interventional treatments for 1-7 years before requesting amputation. Three patients underwent below-knee amputations (BKA) and one had an above-knee amputation (AKA). Target muscles included the soleus, gastrocnemius, and flexor hallucis longus (BKA), and semitendinosus, biceps femoris, and vastus medialis (AKA). Postoperative phantom and residual limb pain symptoms were collected via a telephone survey adapted from the Patient-Reported Outcomes Measurement Information System (PROMIS).

RESULTS

There were no complications related to the TMR procedure. Average follow-up time was 12.75 months. Patients reported varied outcomes: two had RLP and PLP, one had RLP only, and one had PLP only. All patients reported successful prosthetic use.

CONCLUSION

TMR may be performed at the time of amputation for CRPS. Further study is necessary to determine the effect of TMR on pain, pain medication use, prosthesis use, and other domains of function.

Validation of the Japanese version of the Bath CRPS Body Perception Disturbance Scale for CRPS

PURPOSE

Body perception disturbance is a common symptom and may be one of the key targets of treatment intervention in complex regional pain syndrome (CRPS). As a comprehensive assessment tool of body perception in patients with CRPS, the Bath Body Perception Disturbance Scale (BPDS) was developed, and its adequate reliability and validity have been reported. However, there is no available Japanese version. Therefore, this study aimed to develop a Japanese version of BPDS (BPDS-J) and to investigate the validity of this scale in Japanese patients with CRPS.

METHODS

We developed BPDS-J using a forward-backward method. We then assessed 22 patients with CRPS type 1 of the upper limb using BPDS-J, Brief Pain Inventory (BPI), Tampa Scale for Kinesiophobia (TSK), and a two-point discrimination threshold (TPD) on the middle finger. We investigated the internal consistency of BPDS-J and the correlation between BPDS-J and clinical outcomes as a concurrent validity measure.

RESULTS

BPDS-J had good internal consistency (Cronbach's α = 0.73) and was significantly correlated with the TPD ratio (r = 0.65, adjusted p = 0.01) and TSK (r = 0.51, adjusted p = 0.04).

CONCLUSIONS

BPDS-J has good internal consistency and concurrent validity for assessing body perception disturbance in Japanese patients with CRPS. Disturbed body perception may be worth evaluating when managing patients with CRPS using BPDS.